Here are the correct forms of the words to complete the sentences:

1. These **eco-friendly** businesses help recycle your old stuff. (eco-friendly)
2. The campaign has certainly succeeded in raising public **awareness** of the issue. (aware)
3. We bought a TV that was **reduced** from £500 to £350 in the sales. (reduce)
4. The article is full of hints on how to live **sustainably**. (sustainable)
5. Indeed, it could be the worst **environmental** disaster in Europe this century. (environment)